In recent years, a surface mounting type connector mounted to a substrate surface has been used instead of an insertion type connector for inserting a terminal into the substrate from the viewpoint of high density, compactness and efficiency of mounting. This is disclosed in, for example, U.S. Pat. No. 6,866,524.
In U.S. Pat. No. 6,866,524, a structure and a mounting method for mounting the connector of the surface mounting type to the substrate is disclosed. Concretely, the housing is supported by first melting solder interposed between the housing of the connector and the substrate in a state in which the housing is floated on the substrate. The housing attaining this supporting state is positioned such that the terminal is located at a land center by the action of surface tension of second melting solder interposed between the terminal and the land. The positioned housing is then mechanically fixed (e.g., fastened by screws) onto the substrate in a state in which the first and second melting solders are respectively solidified by cooling.
When the number of terminals of the connector is generally increased, it becomes difficult to secure coplanarity of terminal tips (specifically, a joining part to the land). Further, it becomes difficult to secure connection of all the terminals and the corresponding lands by the influences of a warp of the substrate and a warp of the housing.
In the construction, at a time point before the melting solder is cooled and solidified, the terminal is positioned in the corresponding land by a self alignment effect using the second melting solder in a planar direction of the substrate. Further, the terminal is not positioned in the corresponding land and is in a free state in a thickness direction of the substrate, i.e., in a height direction with respect to a substrate surface. Accordingly, a warp is caused in the substrate and the housing by thermal expansion in a reflow process (specifically, a melting state of the first and second melting solders) so that the distance between the terminal and the substrate surface is dispersed. Namely, there is a problem of a reduction in connection reliability.